Method for improving rotating bending fatigue performance of locomotive axle steel

Abstract

The present invention discloses a method for improving rotating bending fatigue performance of locomotive axle steel, and belongs to the technical field of metal material surface nanocrystallization. The method uses surface mechanical rolling treatment technology for surface nanocrystallization of locomotive axle LZ50 steel, and the treatment process is performed on a numerical control surface nanocrystallization treatment system. After the surface nanocrystallization treatment, a LZ50 steel surface structure is transformed into a gradient nano structure, the outermost layer crystal grain size is 10-50nm, the grain size gradually increases with the increase of the layer depth to the original grain size; the LZ50 steel surface nanocrystallization treatment state surface hardness is in a gradient distribution state, the outermost layer microhardness value is greater than 3.0GPa, and is significantly improved compared with the matrix hardness value; and the LZ50 steel surface nanocrystallization treatment state surface roughness is less than 0.4mum, and is significantly improved compared with the turning sate surface roughness. The rotating bending fatigue performance of the locomotive axle LZ50 steel is significantly improved by the surface nanocrystallization treatment.

Description

technical field [0001] The invention relates to the technical field of surface nanometerization of metal materials, in particular to a method for improving the rotational bending fatigue performance of locomotive wheel axle steel. Background technique [0002] As one of the most important components in the running process of rail vehicles, the quality and service performance of locomotive axles are directly related to the safety of rail vehicles. The locomotive wheel axle is mainly affected by the rotating and bending load during service, and fatigue damage induced by fatigue cracks is very likely to occur. If the wheel axle fatigue fracture occurs during the operation of the locomotive and vehicle, it will inevitably cause serious accidents such as train derailment or even rollover. Therefore, improving the fatigue performance of the locomotive axle is of great significance to the safe operation of rolling stock. The current rail vehicle industry generally adopts increasin...

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Problems solved by technology

Although the surface mechanical grinding treatment can obtain a certain thickness of nanostructure layer on the surface of the shaft material, the surface roughness of the material after treatment is relatively high, and the treatment efficiency is low, the cost is high, and there are noise pollution problems during the treatment process.

Methods such as shot peening, ultrasonic shot peening and deep rolling can obtain residual compressive stress layers with different thicknesses on the surface of shaft materials to improve the fatigue performance of shaft materials, but these methods have limited scope for refining the material structure. The thinnest surface layer of the rear shaft material can only reach the sub-micron level. If the residual compressive stress is released during use, its fatigue performance will be difficult to meet the use requirements; in addition, there are problems such as noise and dust treatment in shot peening and ultrasonic shot peening.

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